The present embodiments relate to elasticity imaging. In particular, the present embodiments relate to motion correction in elasticity imaging.
U.S. Pat. Nos. 5,107,837, 5,293,870, 5,178,147, and 6,508,768 describe methods to generate elasticity images using the relative tissue displacement between adjacent frames. Strain, strain rate, modulus, or other parameters corresponding to tissue displacement are detected for generating an elasticity image. U.S. Pat. No. 6,558,324 describes methods to represent elasticity using color coding. Other forms of elasticity imaging include shear and longitudinal wave imaging. Acoustic radiation force imaging also indicates the elasticity of tissue.
Elasticity imaging relies on differences in compression or tissue response over time to stress. Tissue deformation parameters, such as longitudinal and shear strain, or shear wave propagation parameters are secondary order estimates from phase or displacement information. Given a period over which data is collected, the elasticity imaging is susceptible to motion artifacts. It is a challenge to avoid displacement from sources other than the compression or stress for measuring elasticity. The patient may move, the transducer probe may move, and anatomy may move. The result is low quality, biased, low repeatability elasticity imaging.
For two-dimensional elasticity imaging, motion correction is applied to frames of echo data prior to elasticity estimation. The motion correction may remove some undesired distortions, but does not deal with out-of-plane motion.